source3/rpc_parse/parse_prs.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    Samba memory buffer functions
   4    Copyright (C) Andrew Tridgell              1992-1997
   5    Copyright (C) Luke Kenneth Casson Leighton 1996-1997
   6    Copyright (C) Jeremy Allison               1999
   7    Copyright (C) Andrew Bartlett              2003.
   8
   9    This program is free software; you can redistribute it and/or modify
  10    it under the terms of the GNU General Public License as published by
  11    the Free Software Foundation; either version 3 of the License, or
  12    (at your option) any later version.
  13
  14    This program is distributed in the hope that it will be useful,
  15    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17    GNU General Public License for more details.
  18
  19    You should have received a copy of the GNU General Public License
  20    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  21 */
  22
  23 #include "includes.h"
  24 #include "../librpc/gen_ndr/ndr_schannel.h"
  25
  26 #undef DBGC_CLASS
  27 #define DBGC_CLASS DBGC_RPC_PARSE
  28
  29 /**
  30  * Dump a prs to a file: from the current location through to the end.
  31  **/
  32 void prs_dump(const char *name, int v, prs_struct *ps)
  33 {
  34         prs_dump_region(name, v, ps, ps->data_offset, ps->buffer_size);
  35 }
  36
  37 /**
  38  * Dump from the start of the prs to the current location.
  39  **/
  40 void prs_dump_before(const char *name, int v, prs_struct *ps)
  41 {
  42         prs_dump_region(name, v, ps, 0, ps->data_offset);
  43 }
  44
  45 /**
  46  * Dump everything from the start of the prs up to the current location.
  47  **/
  48 void prs_dump_region(const char *name, int v, prs_struct *ps,
  49                      int from_off, int to_off)
  50 {
  51         int fd, i;
  52         char *fname = NULL;
  53         ssize_t sz;
  54         if (DEBUGLEVEL < 50) return;
  55         for (i=1;i<100;i++) {
  56                 if (v != -1) {
  57                         if (asprintf(&fname,"/tmp/%s_%d.%d.prs", name, v, i) < 0) {
  58                                 return;
  59                         }
  60                 } else {
  61                         if (asprintf(&fname,"/tmp/%s.%d.prs", name, i) < 0) {
  62                                 return;
  63                         }
  64                 }
  65                 fd = open(fname, O_WRONLY|O_CREAT|O_EXCL, 0644);
  66                 if (fd != -1 || errno != EEXIST) break;
  67         }
  68         if (fd != -1) {
  69                 sz = write(fd, ps->data_p + from_off, to_off - from_off);
  70                 i = close(fd);
  71                 if ( (sz != to_off-from_off) || (i != 0) ) {
  72                         DEBUG(0,("Error writing/closing %s: %ld!=%ld %d\n", fname, (unsigned long)sz, (unsigned long)to_off-from_off, i ));
  73                 } else {
  74                         DEBUG(0,("created %s\n", fname));
  75                 }
  76         }
  77         SAFE_FREE(fname);
  78 }
  79
  80 /*******************************************************************
  81  Debug output for parsing info
  82
  83  XXXX side-effect of this function is to increase the debug depth XXXX.
  84
  85 ********************************************************************/
  86
  87 void prs_debug(prs_struct *ps, int depth, const char *desc, const char *fn_name)
  88 {
  89         DEBUG(5+depth, ("%s%06x %s %s\n", tab_depth(5+depth,depth), ps->data_offset, fn_name, desc));
  90 }
  91
  92 /**
  93  * Initialise an expandable parse structure.
  94  *
  95  * @param size Initial buffer size.  If >0, a new buffer will be
  96  * created with malloc().
  97  *
  98  * @return False if allocation fails, otherwise True.
  99  **/
 100
 101 bool prs_init(prs_struct *ps, uint32 size, TALLOC_CTX *ctx, bool io)
 102 {
 103         ZERO_STRUCTP(ps);
 104         ps->io = io;
 105         ps->bigendian_data = RPC_LITTLE_ENDIAN;
 106         ps->align = RPC_PARSE_ALIGN;
 107         ps->is_dynamic = False;
 108         ps->data_offset = 0;
 109         ps->buffer_size = 0;
 110         ps->data_p = NULL;
 111         ps->mem_ctx = ctx;
 112
 113         if (size != 0) {
 114                 ps->buffer_size = size;
 115                 if((ps->data_p = (char *)SMB_MALLOC((size_t)size)) == NULL) {
 116                         DEBUG(0,("prs_init: malloc fail for %u bytes.\n", (unsigned int)size));
 117                         return False;
 118                 }
 119                 memset(ps->data_p, '\0', (size_t)size);
 120                 ps->is_dynamic = True; /* We own this memory. */
 121         } else if (MARSHALLING(ps)) {
 122                 /* If size is zero and we're marshalling we should allocate memory on demand. */
 123                 ps->is_dynamic = True;
 124         }
 125
 126         return True;
 127 }
 128
 129 /*******************************************************************
 130  Delete the memory in a parse structure - if we own it.
 131
 132  NOTE: Contrary to the somewhat confusing naming, this function is not
 133        intended for freeing memory allocated by prs_alloc_mem().  That memory
 134        is attached to the talloc context given by ps->mem_ctx.
 135  ********************************************************************/
 136
 137 void prs_mem_free(prs_struct *ps)
 138 {
 139         if(ps->is_dynamic)
 140                 SAFE_FREE(ps->data_p);
 141         ps->is_dynamic = False;
 142         ps->buffer_size = 0;
 143         ps->data_offset = 0;
 144 }
 145
 146 /*******************************************************************
 147  Clear the memory in a parse structure.
 148  ********************************************************************/
 149
 150 void prs_mem_clear(prs_struct *ps)
 151 {
 152         if (ps->buffer_size)
 153                 memset(ps->data_p, '\0', (size_t)ps->buffer_size);
 154 }
 155
 156 /*******************************************************************
 157  Allocate memory when unmarshalling... Always zero clears.
 158  ********************************************************************/
 159
 160 #if defined(PARANOID_MALLOC_CHECKER)
 161 char *prs_alloc_mem_(prs_struct *ps, size_t size, unsigned int count)
 162 #else
 163 char *prs_alloc_mem(prs_struct *ps, size_t size, unsigned int count)
 164 #endif
 165 {
 166         char *ret = NULL;
 167
 168         if (size && count) {
 169                 /* We can't call the type-safe version here. */
 170                 ret = (char *)_talloc_zero_array(ps->mem_ctx, size, count,
 171                                                  "parse_prs");
 172         }
 173         return ret;
 174 }
 175
 176 /*******************************************************************
 177  Return the current talloc context we're using.
 178  ********************************************************************/
 179
 180 TALLOC_CTX *prs_get_mem_context(prs_struct *ps)
 181 {
 182         return ps->mem_ctx;
 183 }
 184
 185 /*******************************************************************
 186  Hand some already allocated memory to a prs_struct.
 187  ********************************************************************/
 188
 189 void prs_give_memory(prs_struct *ps, char *buf, uint32 size, bool is_dynamic)
 190 {
 191         ps->is_dynamic = is_dynamic;
 192         ps->data_p = buf;
 193         ps->buffer_size = size;
 194 }
 195
 196 /*******************************************************************
 197  Take some memory back from a prs_struct.
 198  ********************************************************************/
 199
 200 char *prs_take_memory(prs_struct *ps, uint32 *psize)
 201 {
 202         char *ret = ps->data_p;
 203         if(psize)
 204                 *psize = ps->buffer_size;
 205         ps->is_dynamic = False;
 206         prs_mem_free(ps);
 207         return ret;
 208 }
 209
 210 /*******************************************************************
 211  Set a prs_struct to exactly a given size. Will grow or tuncate if neccessary.
 212  ********************************************************************/
 213
 214 bool prs_set_buffer_size(prs_struct *ps, uint32 newsize)
 215 {
 216         if (newsize > ps->buffer_size)
 217                 return prs_force_grow(ps, newsize - ps->buffer_size);
 218
 219         if (newsize < ps->buffer_size) {
 220                 ps->buffer_size = newsize;
 221
 222                 /* newsize == 0 acts as a free and set pointer to NULL */
 223                 if (newsize == 0) {
 224                         SAFE_FREE(ps->data_p);
 225                 } else {
 226                         ps->data_p = (char *)SMB_REALLOC(ps->data_p, newsize);
 227
 228                         if (ps->data_p == NULL) {
 229                                 DEBUG(0,("prs_set_buffer_size: Realloc failure for size %u.\n",
 230                                         (unsigned int)newsize));
 231                                 DEBUG(0,("prs_set_buffer_size: Reason %s\n",strerror(errno)));
 232                                 return False;
 233                         }
 234                 }
 235         }
 236
 237         return True;
 238 }
 239
 240 /*******************************************************************
 241  Attempt, if needed, to grow a data buffer.
 242  Also depends on the data stream mode (io).
 243  ********************************************************************/
 244
 245 bool prs_grow(prs_struct *ps, uint32 extra_space)
 246 {
 247         uint32 new_size;
 248
 249         ps->grow_size = MAX(ps->grow_size, ps->data_offset + extra_space);
 250
 251         if(ps->data_offset + extra_space <= ps->buffer_size)
 252                 return True;
 253
 254         /*
 255          * We cannot grow the buffer if we're not reading
 256          * into the prs_struct, or if we don't own the memory.
 257          */
 258
 259         if(UNMARSHALLING(ps) || !ps->is_dynamic) {
 260                 DEBUG(0,("prs_grow: Buffer overflow - unable to expand buffer by %u bytes.\n",
 261                                 (unsigned int)extra_space));
 262                 return False;
 263         }
 264
 265         /*
 266          * Decide how much extra space we really need.
 267          */
 268
 269         extra_space -= (ps->buffer_size - ps->data_offset);
 270         if(ps->buffer_size == 0) {
 271
 272                 /*
 273                  * Start with 128 bytes (arbitrary value), enough for small rpc
 274                  * requests
 275                  */
 276                 new_size = MAX(128, extra_space);
 277
 278                 if((ps->data_p = (char *)SMB_MALLOC(new_size)) == NULL) {
 279                         DEBUG(0,("prs_grow: Malloc failure for size %u.\n", (unsigned int)new_size));
 280                         return False;
 281                 }
 282                 memset(ps->data_p, '\0', (size_t)new_size );
 283         } else {
 284                 /*
 285                  * If the current buffer size is bigger than the space needed,
 286                  * just double it, else add extra_space. Always keep 64 bytes
 287                  * more, so that after we added a large blob we don't have to
 288                  * realloc immediately again.
 289                  */
 290                 new_size = MAX(ps->buffer_size*2,
 291                                ps->buffer_size + extra_space + 64);
 292
 293                 if ((ps->data_p = (char *)SMB_REALLOC(ps->data_p, new_size)) == NULL) {
 294                         DEBUG(0,("prs_grow: Realloc failure for size %u.\n",
 295                                 (unsigned int)new_size));
 296                         return False;
 297                 }
 298
 299                 memset(&ps->data_p[ps->buffer_size], '\0', (size_t)(new_size - ps->buffer_size));
 300         }
 301         ps->buffer_size = new_size;
 302
 303         return True;
 304 }
 305
 306 /*******************************************************************
 307  Attempt to force a data buffer to grow by len bytes.
 308  This is only used when appending more data onto a prs_struct
 309  when reading an rpc reply, before unmarshalling it.
 310  ********************************************************************/
 311
 312 bool prs_force_grow(prs_struct *ps, uint32 extra_space)
 313 {
 314         uint32 new_size = ps->buffer_size + extra_space;
 315
 316         if(!UNMARSHALLING(ps) || !ps->is_dynamic) {
 317                 DEBUG(0,("prs_force_grow: Buffer overflow - unable to expand buffer by %u bytes.\n",
 318                                 (unsigned int)extra_space));
 319                 return False;
 320         }
 321
 322         if((ps->data_p = (char *)SMB_REALLOC(ps->data_p, new_size)) == NULL) {
 323                 DEBUG(0,("prs_force_grow: Realloc failure for size %u.\n",
 324                         (unsigned int)new_size));
 325                 return False;
 326         }
 327
 328         memset(&ps->data_p[ps->buffer_size], '\0', (size_t)(new_size - ps->buffer_size));
 329
 330         ps->buffer_size = new_size;
 331
 332         return True;
 333 }
 334
 335 /*******************************************************************
 336  Get the data pointer (external interface).
 337 ********************************************************************/
 338
 339 char *prs_data_p(prs_struct *ps)
 340 {
 341         return ps->data_p;
 342 }
 343
 344 /*******************************************************************
 345  Get the current data size (external interface).
 346  ********************************************************************/
 347
 348 uint32 prs_data_size(prs_struct *ps)
 349 {
 350         return ps->buffer_size;
 351 }
 352
 353 /*******************************************************************
 354  Fetch the current offset (external interface).
 355  ********************************************************************/
 356
 357 uint32 prs_offset(prs_struct *ps)
 358 {
 359         return ps->data_offset;
 360 }
 361
 362 /*******************************************************************
 363  Set the current offset (external interface).
 364  ********************************************************************/
 365
 366 bool prs_set_offset(prs_struct *ps, uint32 offset)
 367 {
 368         if ((offset > ps->data_offset)
 369             && !prs_grow(ps, offset - ps->data_offset)) {
 370                 return False;
 371         }
 372
 373         ps->data_offset = offset;
 374         return True;
 375 }
 376
 377 /*******************************************************************
 378  Append the data from one parse_struct into another.
 379  ********************************************************************/
 380
 381 bool prs_append_prs_data(prs_struct *dst, prs_struct *src)
 382 {
 383         if (prs_offset(src) == 0)
 384                 return True;
 385
 386         if(!prs_grow(dst, prs_offset(src)))
 387                 return False;
 388
 389         memcpy(&dst->data_p[dst->data_offset], src->data_p, (size_t)prs_offset(src));
 390         dst->data_offset += prs_offset(src);
 391
 392         return True;
 393 }
 394
 395 /*******************************************************************
 396  Append some data from one parse_struct into another.
 397  ********************************************************************/
 398
 399 bool prs_append_some_data(prs_struct *dst, void *src_base, uint32_t start,
 400                           uint32_t len)
 401 {
 402         if (len == 0) {
 403                 return true;
 404         }
 405
 406         if(!prs_grow(dst, len)) {
 407                 return false;
 408         }
 409
 410         memcpy(&dst->data_p[dst->data_offset], ((char *)src_base) + start, (size_t)len);
 411         dst->data_offset += len;
 412         return true;
 413 }
 414
 415 bool prs_append_some_prs_data(prs_struct *dst, prs_struct *src, int32 start,
 416                               uint32 len)
 417 {
 418         return prs_append_some_data(dst, src->data_p, start, len);
 419 }
 420
 421 /*******************************************************************
 422  Append the data from a buffer into a parse_struct.
 423  ********************************************************************/
 424
 425 bool prs_copy_data_in(prs_struct *dst, const char *src, uint32 len)
 426 {
 427         if (len == 0)
 428                 return True;
 429
 430         if(!prs_grow(dst, len))
 431                 return False;
 432
 433         memcpy(&dst->data_p[dst->data_offset], src, (size_t)len);
 434         dst->data_offset += len;
 435
 436         return True;
 437 }
 438
 439 /*******************************************************************
 440  Copy some data from a parse_struct into a buffer.
 441  ********************************************************************/
 442
 443 bool prs_copy_data_out(char *dst, prs_struct *src, uint32 len)
 444 {
 445         if (len == 0)
 446                 return True;
 447
 448         if(!prs_mem_get(src, len))
 449                 return False;
 450
 451         memcpy(dst, &src->data_p[src->data_offset], (size_t)len);
 452         src->data_offset += len;
 453
 454         return True;
 455 }
 456
 457 /*******************************************************************
 458  Copy all the data from a parse_struct into a buffer.
 459  ********************************************************************/
 460
 461 bool prs_copy_all_data_out(char *dst, prs_struct *src)
 462 {
 463         uint32 len = prs_offset(src);
 464
 465         if (!len)
 466                 return True;
 467
 468         prs_set_offset(src, 0);
 469         return prs_copy_data_out(dst, src, len);
 470 }
 471
 472 /*******************************************************************
 473  Set the data as X-endian (external interface).
 474  ********************************************************************/
 475
 476 void prs_set_endian_data(prs_struct *ps, bool endian)
 477 {
 478         ps->bigendian_data = endian;
 479 }
 480
 481 /*******************************************************************
 482  Align a the data_len to a multiple of align bytes - filling with
 483  zeros.
 484  ********************************************************************/
 485
 486 bool prs_align(prs_struct *ps)
 487 {
 488         uint32 mod = ps->data_offset & (ps->align-1);
 489
 490         if (ps->align != 0 && mod != 0) {
 491                 uint32 extra_space = (ps->align - mod);
 492                 if(!prs_grow(ps, extra_space))
 493                         return False;
 494                 memset(&ps->data_p[ps->data_offset], '\0', (size_t)extra_space);
 495                 ps->data_offset += extra_space;
 496         }
 497
 498         return True;
 499 }
 500
 501 /******************************************************************
 502  Align on a 2 byte boundary
 503  *****************************************************************/
 504
 505 bool prs_align_uint16(prs_struct *ps)
 506 {
 507         bool ret;
 508         uint8 old_align = ps->align;
 509
 510         ps->align = 2;
 511         ret = prs_align(ps);
 512         ps->align = old_align;
 513
 514         return ret;
 515 }
 516
 517 /******************************************************************
 518  Align on a 8 byte boundary
 519  *****************************************************************/
 520
 521 bool prs_align_uint64(prs_struct *ps)
 522 {
 523         bool ret;
 524         uint8 old_align = ps->align;
 525
 526         ps->align = 8;
 527         ret = prs_align(ps);
 528         ps->align = old_align;
 529
 530         return ret;
 531 }
 532
 533 /******************************************************************
 534  Align on a specific byte boundary
 535  *****************************************************************/
 536
 537 bool prs_align_custom(prs_struct *ps, uint8 boundary)
 538 {
 539         bool ret;
 540         uint8 old_align = ps->align;
 541
 542         ps->align = boundary;
 543         ret = prs_align(ps);
 544         ps->align = old_align;
 545
 546         return ret;
 547 }
 548
 549
 550
 551 /*******************************************************************
 552  Align only if required (for the unistr2 string mainly)
 553  ********************************************************************/
 554
 555 bool prs_align_needed(prs_struct *ps, uint32 needed)
 556 {
 557         if (needed==0)
 558                 return True;
 559         else
 560                 return prs_align(ps);
 561 }
 562
 563 /*******************************************************************
 564  Ensure we can read/write to a given offset.
 565  ********************************************************************/
 566
 567 char *prs_mem_get(prs_struct *ps, uint32 extra_size)
 568 {
 569         if(UNMARSHALLING(ps)) {
 570                 /*
 571                  * If reading, ensure that we can read the requested size item.
 572                  */
 573                 if (ps->data_offset + extra_size > ps->buffer_size) {
 574                         DEBUG(0,("prs_mem_get: reading data of size %u would overrun "
 575                                 "buffer by %u bytes.\n",
 576                                 (unsigned int)extra_size,
 577                                 (unsigned int)(ps->data_offset + extra_size - ps->buffer_size) ));
 578                         return NULL;
 579                 }
 580         } else {
 581                 /*
 582                  * Writing - grow the buffer if needed.
 583                  */
 584                 if(!prs_grow(ps, extra_size))
 585                         return NULL;
 586         }
 587         return &ps->data_p[ps->data_offset];
 588 }
 589
 590 /*******************************************************************
 591  Change the struct type.
 592  ********************************************************************/
 593
 594 void prs_switch_type(prs_struct *ps, bool io)
 595 {
 596         if ((ps->io ^ io) == True)
 597                 ps->io=io;
 598 }
 599
 600 /*******************************************************************
 601  Force a prs_struct to be dynamic even when it's size is 0.
 602  ********************************************************************/
 603
 604 void prs_force_dynamic(prs_struct *ps)
 605 {
 606         ps->is_dynamic=True;
 607 }
 608
 609 /*******************************************************************
 610  Associate a session key with a parse struct.
 611  ********************************************************************/
 612
 613 void prs_set_session_key(prs_struct *ps, const char sess_key[16])
 614 {
 615         ps->sess_key = sess_key;
 616 }
 617
 618 /*******************************************************************
 619  Stream a uint8.
 620  ********************************************************************/
 621
 622 bool prs_uint8(const char *name, prs_struct *ps, int depth, uint8 *data8)
 623 {
 624         char *q = prs_mem_get(ps, 1);
 625         if (q == NULL)
 626                 return False;
 627
 628         if (UNMARSHALLING(ps))
 629                 *data8 = CVAL(q,0);
 630         else
 631                 SCVAL(q,0,*data8);
 632
 633         DEBUGADD(5,("%s%04x %s: %02x\n", tab_depth(5,depth), ps->data_offset, name, *data8));
 634
 635         ps->data_offset += 1;
 636
 637         return True;
 638 }
 639
 640 /*******************************************************************
 641  Stream a uint16.
 642  ********************************************************************/
 643
 644 bool prs_uint16(const char *name, prs_struct *ps, int depth, uint16 *data16)
 645 {
 646         char *q = prs_mem_get(ps, sizeof(uint16));
 647         if (q == NULL)
 648                 return False;
 649
 650         if (UNMARSHALLING(ps)) {
 651                 if (ps->bigendian_data)
 652                         *data16 = RSVAL(q,0);
 653                 else
 654                         *data16 = SVAL(q,0);
 655         } else {
 656                 if (ps->bigendian_data)
 657                         RSSVAL(q,0,*data16);
 658                 else
 659                         SSVAL(q,0,*data16);
 660         }
 661
 662         DEBUGADD(5,("%s%04x %s: %04x\n", tab_depth(5,depth), ps->data_offset, name, *data16));
 663
 664         ps->data_offset += sizeof(uint16);
 665
 666         return True;
 667 }
 668
 669 /*******************************************************************
 670  Stream a uint32.
 671  ********************************************************************/
 672
 673 bool prs_uint32(const char *name, prs_struct *ps, int depth, uint32 *data32)
 674 {
 675         char *q = prs_mem_get(ps, sizeof(uint32));
 676         if (q == NULL)
 677                 return False;
 678
 679         if (UNMARSHALLING(ps)) {
 680                 if (ps->bigendian_data)
 681                         *data32 = RIVAL(q,0);
 682                 else
 683                         *data32 = IVAL(q,0);
 684         } else {
 685                 if (ps->bigendian_data)
 686                         RSIVAL(q,0,*data32);
 687                 else
 688                         SIVAL(q,0,*data32);
 689         }
 690
 691         DEBUGADD(5,("%s%04x %s: %08x\n", tab_depth(5,depth), ps->data_offset, name, *data32));
 692
 693         ps->data_offset += sizeof(uint32);
 694
 695         return True;
 696 }
 697
 698 /*******************************************************************
 699  Stream an int32.
 700  ********************************************************************/
 701
 702 bool prs_int32(const char *name, prs_struct *ps, int depth, int32 *data32)
 703 {
 704         char *q = prs_mem_get(ps, sizeof(int32));
 705         if (q == NULL)
 706                 return False;
 707
 708         if (UNMARSHALLING(ps)) {
 709                 if (ps->bigendian_data)
 710                         *data32 = RIVALS(q,0);
 711                 else
 712                         *data32 = IVALS(q,0);
 713         } else {
 714                 if (ps->bigendian_data)
 715                         RSIVALS(q,0,*data32);
 716                 else
 717                         SIVALS(q,0,*data32);
 718         }
 719
 720         DEBUGADD(5,("%s%04x %s: %08x\n", tab_depth(5,depth), ps->data_offset, name, *data32));
 721
 722         ps->data_offset += sizeof(int32);
 723
 724         return True;
 725 }
 726
 727 /*******************************************************************
 728  Stream a uint64_struct
 729  ********************************************************************/
 730 bool prs_uint64(const char *name, prs_struct *ps, int depth, uint64 *data64)
 731 {
 732         if (UNMARSHALLING(ps)) {
 733                 uint32 high, low;
 734
 735                 if (!prs_uint32(name, ps, depth+1, &low))
 736                         return False;
 737
 738                 if (!prs_uint32(name, ps, depth+1, &high))
 739                         return False;
 740
 741                 *data64 = ((uint64_t)high << 32) + low;
 742
 743                 return True;
 744         } else {
 745                 uint32 high = (*data64) >> 32, low = (*data64) & 0xFFFFFFFF;
 746                 return prs_uint32(name, ps, depth+1, &low) &&
 747                            prs_uint32(name, ps, depth+1, &high);
 748         }
 749 }
 750
 751 /*******************************************************************
 752  Stream a DCE error code
 753  ********************************************************************/
 754
 755 bool prs_dcerpc_status(const char *name, prs_struct *ps, int depth, NTSTATUS *status)
 756 {
 757         char *q = prs_mem_get(ps, sizeof(uint32));
 758         if (q == NULL)
 759                 return False;
 760
 761         if (UNMARSHALLING(ps)) {
 762                 if (ps->bigendian_data)
 763                         *status = NT_STATUS(RIVAL(q,0));
 764                 else
 765                         *status = NT_STATUS(IVAL(q,0));
 766         } else {
 767                 if (ps->bigendian_data)
 768                         RSIVAL(q,0,NT_STATUS_V(*status));
 769                 else
 770                         SIVAL(q,0,NT_STATUS_V(*status));
 771         }
 772
 773         DEBUGADD(5,("%s%04x %s: %s\n", tab_depth(5,depth), ps->data_offset, name,
 774                  dcerpc_errstr(debug_ctx(), NT_STATUS_V(*status))));
 775
 776         ps->data_offset += sizeof(uint32);
 777
 778         return True;
 779 }
 780
 781 /******************************************************************
 782  Stream an array of uint8s. Length is number of uint8s.
 783  ********************************************************************/
 784
 785 bool prs_uint8s(bool charmode, const char *name, prs_struct *ps, int depth, uint8 *data8s, int len)
 786 {
 787         int i;
 788         char *q = prs_mem_get(ps, len);
 789         if (q == NULL)
 790                 return False;
 791
 792         if (UNMARSHALLING(ps)) {
 793                 for (i = 0; i < len; i++)
 794                         data8s[i] = CVAL(q,i);
 795         } else {
 796                 for (i = 0; i < len; i++)
 797                         SCVAL(q, i, data8s[i]);
 798         }
 799
 800         DEBUGADD(5,("%s%04x %s: ", tab_depth(5,depth), ps->data_offset ,name));
 801         if (charmode)
 802                 print_asc(5, (unsigned char*)data8s, len);
 803         else {
 804                 for (i = 0; i < len; i++)
 805                         DEBUGADD(5,("%02x ", data8s[i]));
 806         }
 807         DEBUGADD(5,("\n"));
 808
 809         ps->data_offset += len;
 810
 811         return True;
 812 }
 813
 814 /******************************************************************
 815  Stream an array of uint16s. Length is number of uint16s.
 816  ********************************************************************/
 817
 818 bool prs_uint16s(bool charmode, const char *name, prs_struct *ps, int depth, uint16 *data16s, int len)
 819 {
 820         int i;
 821         char *q = prs_mem_get(ps, len * sizeof(uint16));
 822         if (q == NULL)
 823                 return False;
 824
 825         if (UNMARSHALLING(ps)) {
 826                 if (ps->bigendian_data) {
 827                         for (i = 0; i < len; i++)
 828                                 data16s[i] = RSVAL(q, 2*i);
 829                 } else {
 830                         for (i = 0; i < len; i++)
 831                                 data16s[i] = SVAL(q, 2*i);
 832                 }
 833         } else {
 834                 if (ps->bigendian_data) {
 835                         for (i = 0; i < len; i++)
 836                                 RSSVAL(q, 2*i, data16s[i]);
 837                 } else {
 838                         for (i = 0; i < len; i++)
 839                                 SSVAL(q, 2*i, data16s[i]);
 840                 }
 841         }
 842
 843         DEBUGADD(5,("%s%04x %s: ", tab_depth(5,depth), ps->data_offset, name));
 844         if (charmode)
 845                 print_asc(5, (unsigned char*)data16s, 2*len);
 846         else {
 847                 for (i = 0; i < len; i++)
 848                         DEBUGADD(5,("%04x ", data16s[i]));
 849         }
 850         DEBUGADD(5,("\n"));
 851
 852         ps->data_offset += (len * sizeof(uint16));
 853
 854         return True;
 855 }
 856
 857 /******************************************************************
 858  Stream an array of uint32s. Length is number of uint32s.
 859  ********************************************************************/
 860
 861 bool prs_uint32s(bool charmode, const char *name, prs_struct *ps, int depth, uint32 *data32s, int len)
 862 {
 863         int i;
 864         char *q = prs_mem_get(ps, len * sizeof(uint32));
 865         if (q == NULL)
 866                 return False;
 867
 868         if (UNMARSHALLING(ps)) {
 869                 if (ps->bigendian_data) {
 870                         for (i = 0; i < len; i++)
 871                                 data32s[i] = RIVAL(q, 4*i);
 872                 } else {
 873                         for (i = 0; i < len; i++)
 874                                 data32s[i] = IVAL(q, 4*i);
 875                 }
 876         } else {
 877                 if (ps->bigendian_data) {
 878                         for (i = 0; i < len; i++)
 879                                 RSIVAL(q, 4*i, data32s[i]);
 880                 } else {
 881                         for (i = 0; i < len; i++)
 882                                 SIVAL(q, 4*i, data32s[i]);
 883                 }
 884         }
 885
 886         DEBUGADD(5,("%s%04x %s: ", tab_depth(5,depth), ps->data_offset, name));
 887         if (charmode)
 888                 print_asc(5, (unsigned char*)data32s, 4*len);
 889         else {
 890                 for (i = 0; i < len; i++)
 891                         DEBUGADD(5,("%08x ", data32s[i]));
 892         }
 893         DEBUGADD(5,("\n"));
 894
 895         ps->data_offset += (len * sizeof(uint32));
 896
 897         return True;
 898 }
 899
 900 /*******************************************************************
 901  Stream a unicode  null-terminated string. As the string is already
 902  in little-endian format then do it as a stream of bytes.
 903  ********************************************************************/
 904
 905 bool prs_unistr(const char *name, prs_struct *ps, int depth, UNISTR *str)
 906 {
 907         unsigned int len = 0;
 908         unsigned char *p = (unsigned char *)str->buffer;
 909         uint8 *start;
 910         char *q;
 911         uint32 max_len;
 912         uint16* ptr;
 913
 914         if (MARSHALLING(ps)) {
 915
 916                 for(len = 0; str->buffer[len] != 0; len++)
 917                         ;
 918
 919                 q = prs_mem_get(ps, (len+1)*2);
 920                 if (q == NULL)
 921                         return False;
 922
 923                 start = (uint8*)q;
 924
 925                 for(len = 0; str->buffer[len] != 0; len++) {
 926                         if(ps->bigendian_data) {
 927                                 /* swap bytes - p is little endian, q is big endian. */
 928                                 q[0] = (char)p[1];
 929                                 q[1] = (char)p[0];
 930                                 p += 2;
 931                                 q += 2;
 932                         }
 933                         else
 934                         {
 935                                 q[0] = (char)p[0];
 936                                 q[1] = (char)p[1];
 937                                 p += 2;
 938                                 q += 2;
 939                         }
 940                 }
 941
 942                 /*
 943                  * even if the string is 'empty' (only an \0 char)
 944                  * at this point the leading \0 hasn't been parsed.
 945                  * so parse it now
 946                  */
 947
 948                 q[0] = 0;
 949                 q[1] = 0;
 950                 q += 2;
 951
 952                 len++;
 953
 954                 DEBUGADD(5,("%s%04x %s: ", tab_depth(5,depth), ps->data_offset, name));
 955                 print_asc(5, (unsigned char*)start, 2*len);
 956                 DEBUGADD(5, ("\n"));
 957         }
 958         else { /* unmarshalling */
 959
 960                 uint32 alloc_len = 0;
 961                 q = ps->data_p + prs_offset(ps);
 962
 963                 /*
 964                  * Work out how much space we need and talloc it.
 965                  */
 966                 max_len = (ps->buffer_size - ps->data_offset)/sizeof(uint16);
 967
 968                 /* the test of the value of *ptr helps to catch the circumstance
 969                    where we have an emtpty (non-existent) string in the buffer */
 970                 for ( ptr = (uint16 *)q; *ptr++ && (alloc_len <= max_len); alloc_len++)
 971                         /* do nothing */
 972                         ;
 973
 974                 if (alloc_len < max_len)
 975                         alloc_len += 1;
 976
 977                 /* should we allocate anything at all? */
 978                 str->buffer = PRS_ALLOC_MEM(ps,uint16,alloc_len);
 979                 if ((str->buffer == NULL) && (alloc_len > 0))
 980                         return False;
 981
 982                 p = (unsigned char *)str->buffer;
 983
 984                 len = 0;
 985                 /* the (len < alloc_len) test is to prevent us from overwriting
 986                    memory that is not ours...if we get that far, we have a non-null
 987                    terminated string in the buffer and have messed up somewhere */
 988                 while ((len < alloc_len) && (*(uint16 *)q != 0)) {
 989                         if(ps->bigendian_data)
 990                         {
 991                                 /* swap bytes - q is big endian, p is little endian. */
 992                                 p[0] = (unsigned char)q[1];
 993                                 p[1] = (unsigned char)q[0];
 994                                 p += 2;
 995                                 q += 2;
 996                         } else {
 997
 998                                 p[0] = (unsigned char)q[0];
 999                                 p[1] = (unsigned char)q[1];
1000                                 p += 2;
1001                                 q += 2;
1002                         }
1003
1004                         len++;
1005                 }
1006                 if (len < alloc_len) {
1007                         /* NULL terminate the UNISTR */
1008                         str->buffer[len++] = '\0';
1009                 }
1010
1011                 DEBUGADD(5,("%s%04x %s: ", tab_depth(5,depth), ps->data_offset, name));
1012                 print_asc(5, (unsigned char*)str->buffer, 2*len);
1013                 DEBUGADD(5, ("\n"));
1014         }
1015
1016         /* set the offset in the prs_struct; 'len' points to the
1017            terminiating NULL in the UNISTR so we need to go one more
1018            uint16 */
1019         ps->data_offset += (len)*2;
1020
1021         return True;
1022 }
1023
1024
1025 /*******************************************************************
1026  Stream a null-terminated string.  len is strlen, and therefore does
1027  not include the null-termination character.
1028  ********************************************************************/
1029
1030 bool prs_string(const char *name, prs_struct *ps, int depth, char *str, int max_buf_size)
1031 {
1032         char *q;
1033         int i;
1034         int len;
1035
1036         if (UNMARSHALLING(ps))
1037                 len = strlen(&ps->data_p[ps->data_offset]);
1038         else
1039                 len = strlen(str);
1040
1041         len = MIN(len, (max_buf_size-1));
1042
1043         q = prs_mem_get(ps, len+1);
1044         if (q == NULL)
1045                 return False;
1046
1047         for(i = 0; i < len; i++) {
1048                 if (UNMARSHALLING(ps))
1049                         str[i] = q[i];
1050                 else
1051                         q[i] = str[i];
1052         }
1053
1054         /* The terminating null. */
1055         str[i] = '\0';
1056
1057         if (MARSHALLING(ps)) {
1058                 q[i] = '\0';
1059         }
1060
1061         ps->data_offset += len+1;
1062
1063         dump_data(5+depth, (uint8 *)q, len);
1064
1065         return True;
1066 }
1067
1068 /*******************************************************************
1069  Create a digest over the entire packet (including the data), and
1070  MD5 it with the session key.
1071  ********************************************************************/
1072
1073 static void schannel_digest(struct schannel_auth_struct *a,
1074                           enum pipe_auth_level auth_level,
1075                           struct NL_AUTH_SIGNATURE *verf,
1076                           char *data, size_t data_len,
1077                           uchar digest_final[16])
1078 {
1079         uchar whole_packet_digest[16];
1080         uchar zeros[4];
1081         struct MD5Context ctx3;
1082         uint8_t sig[8];
1083
1084         ZERO_STRUCT(zeros);
1085         ZERO_STRUCT(sig);
1086
1087         SSVAL(sig,0,verf->SignatureAlgorithm);
1088         SSVAL(sig,2,verf->SealAlgorithm);
1089         SSVAL(sig,4,verf->Pad);
1090         SSVAL(sig,6,verf->Flags);
1091
1092         /* verfiy the signature on the packet by MD5 over various bits */
1093         MD5Init(&ctx3);
1094         /* use our sequence number, which ensures the packet is not
1095            out of order */
1096         MD5Update(&ctx3, zeros, sizeof(zeros));
1097         MD5Update(&ctx3, sig, 8);
1098         if (auth_level == PIPE_AUTH_LEVEL_PRIVACY) {
1099                 MD5Update(&ctx3, verf->Confounder, sizeof(verf->Confounder));
1100         }
1101         MD5Update(&ctx3, (const unsigned char *)data, data_len);
1102         MD5Final(whole_packet_digest, &ctx3);
1103         dump_data_pw("whole_packet_digest:\n", whole_packet_digest, sizeof(whole_packet_digest));
1104
1105         /* MD5 this result and the session key, to prove that
1106            only a valid client could had produced this */
1107         hmac_md5(a->sess_key, whole_packet_digest, sizeof(whole_packet_digest), digest_final);
1108 }
1109
1110 /*******************************************************************
1111  Calculate the key with which to encode the data payload
1112  ********************************************************************/
1113
1114 static void schannel_get_sealing_key(struct schannel_auth_struct *a,
1115                                    struct NL_AUTH_SIGNATURE *verf,
1116                                    uchar sealing_key[16])
1117 {
1118         uchar zeros[4];
1119         uchar digest2[16];
1120         uchar sess_kf0[16];
1121         int i;
1122
1123         ZERO_STRUCT(zeros);
1124
1125         for (i = 0; i < sizeof(sess_kf0); i++) {
1126                 sess_kf0[i] = a->sess_key[i] ^ 0xf0;
1127         }
1128
1129         dump_data_pw("sess_kf0:\n", sess_kf0, sizeof(sess_kf0));
1130
1131         /* MD5 of sess_kf0 and 4 zero bytes */
1132         hmac_md5(sess_kf0, zeros, 0x4, digest2);
1133         dump_data_pw("digest2:\n", digest2, sizeof(digest2));
1134
1135         /* MD5 of the above result, plus 8 bytes of sequence number */
1136         hmac_md5(digest2, verf->SequenceNumber, sizeof(verf->SequenceNumber), sealing_key);
1137         dump_data_pw("sealing_key:\n", sealing_key, 16);
1138 }
1139
1140 /*******************************************************************
1141  Encode or Decode the sequence number (which is symmetric)
1142  ********************************************************************/
1143
1144 static void schannel_deal_with_seq_num(struct schannel_auth_struct *a,
1145                                        struct NL_AUTH_SIGNATURE *verf)
1146 {
1147         uchar zeros[4];
1148         uchar sequence_key[16];
1149         uchar digest1[16];
1150
1151         ZERO_STRUCT(zeros);
1152
1153         hmac_md5(a->sess_key, zeros, sizeof(zeros), digest1);
1154         dump_data_pw("(sequence key) digest1:\n", digest1, sizeof(digest1));
1155
1156         hmac_md5(digest1, verf->Checksum, 8, sequence_key);
1157
1158         dump_data_pw("sequence_key:\n", sequence_key, sizeof(sequence_key));
1159
1160         dump_data_pw("seq_num (before):\n", verf->SequenceNumber, sizeof(verf->SequenceNumber));
1161         arcfour_crypt(verf->SequenceNumber, sequence_key, 8);
1162         dump_data_pw("seq_num (after):\n", verf->SequenceNumber, sizeof(verf->SequenceNumber));
1163 }
1164
1165 /*******************************************************************
1166  Encode a blob of data using the schannel alogrithm, also produceing
1167  a checksum over the original data.  We currently only support
1168  signing and sealing togeather - the signing-only code is close, but not
1169  quite compatible with what MS does.
1170  ********************************************************************/
1171
1172 void schannel_encode(struct schannel_auth_struct *a, enum pipe_auth_level auth_level,
1173                    enum schannel_direction direction,
1174                    struct NL_AUTH_SIGNATURE *verf,
1175                    char *data, size_t data_len)
1176 {
1177         uchar digest_final[16];
1178         uchar confounder[8];
1179         uchar seq_num[8];
1180         static const uchar nullbytes[8] = { 0, };
1181
1182         DEBUG(10,("SCHANNEL: schannel_encode seq_num=%d data_len=%lu\n", a->seq_num, (unsigned long)data_len));
1183
1184         /* fill the 'confounder' with random data */
1185         generate_random_buffer(confounder, sizeof(confounder));
1186
1187         dump_data_pw("a->sess_key:\n", a->sess_key, sizeof(a->sess_key));
1188
1189         RSIVAL(seq_num, 0, a->seq_num);
1190
1191         switch (direction) {
1192         case SENDER_IS_INITIATOR:
1193                 SIVAL(seq_num, 4, 0x80);
1194                 break;
1195         case SENDER_IS_ACCEPTOR:
1196                 SIVAL(seq_num, 4, 0x0);
1197                 break;
1198         }
1199
1200         dump_data_pw("verf->SequenceNumber:\n", verf->SequenceNumber, sizeof(verf->SequenceNumber));
1201
1202         if (auth_level == PIPE_AUTH_LEVEL_PRIVACY) {
1203                 verf->SealAlgorithm             = NL_SEAL_RC4;
1204         } else {
1205                 verf->SealAlgorithm             = NL_SEAL_NONE;
1206         }
1207
1208         verf->SignatureAlgorithm        = NL_SIGN_HMAC_MD5;
1209         verf->Pad                       = 0xffff;
1210         verf->Flags                     = 0x0000;
1211
1212         memcpy(verf->SequenceNumber, seq_num, sizeof(verf->SequenceNumber));
1213         memcpy(verf->Checksum, nullbytes, sizeof(verf->Checksum));
1214         memcpy(verf->Confounder, confounder, sizeof(verf->Confounder));
1215
1216         /* produce a digest of the packet to prove it's legit (before we seal it) */
1217         schannel_digest(a, auth_level, verf, data, data_len, digest_final);
1218         memcpy(verf->Checksum, digest_final, sizeof(verf->Checksum));
1219
1220         if (auth_level == PIPE_AUTH_LEVEL_PRIVACY) {
1221                 uchar sealing_key[16];
1222
1223                 /* get the key to encode the data with */
1224                 schannel_get_sealing_key(a, verf, sealing_key);
1225
1226                 /* encode the verification data */
1227                 dump_data_pw("verf->Confounder:\n", verf->Confounder, sizeof(verf->Confounder));
1228                 arcfour_crypt(verf->Confounder, sealing_key, 8);
1229
1230                 dump_data_pw("verf->Confounder_enc:\n", verf->Confounder, sizeof(verf->Confounder));
1231
1232                 /* encode the packet payload */
1233                 dump_data_pw("data:\n", (const unsigned char *)data, data_len);
1234                 arcfour_crypt((unsigned char *)data, sealing_key, data_len);
1235                 dump_data_pw("data_enc:\n", (const unsigned char *)data, data_len);
1236         }
1237
1238         /* encode the sequence number (key based on packet digest) */
1239         /* needs to be done after the sealing, as the original version
1240            is used in the sealing stuff... */
1241         schannel_deal_with_seq_num(a, verf);
1242
1243         return;
1244 }
1245
1246 /*******************************************************************
1247  Decode a blob of data using the schannel alogrithm, also verifiying
1248  a checksum over the original data.  We currently can verify signed messages,
1249  as well as decode sealed messages
1250  ********************************************************************/
1251
1252 bool schannel_decode(struct schannel_auth_struct *a, enum pipe_auth_level auth_level,
1253                    enum schannel_direction direction,
1254                    struct NL_AUTH_SIGNATURE *verf, char *data, size_t data_len)
1255 {
1256         uchar digest_final[16];
1257
1258         static const uchar schannel_seal_sig[8] = SCHANNEL_SEAL_SIGNATURE;
1259         static const uchar schannel_sign_sig[8] = SCHANNEL_SIGN_SIGNATURE;
1260         const uchar *schannel_sig = NULL;
1261
1262         uchar seq_num[8];
1263
1264         DEBUG(10,("SCHANNEL: schannel_decode seq_num=%d data_len=%lu\n", a->seq_num, (unsigned long)data_len));
1265
1266         if (auth_level == PIPE_AUTH_LEVEL_PRIVACY) {
1267                 schannel_sig = schannel_seal_sig;
1268         } else {
1269                 schannel_sig = schannel_sign_sig;
1270         }
1271
1272         /* Create the expected sequence number for comparison */
1273         RSIVAL(seq_num, 0, a->seq_num);
1274
1275         switch (direction) {
1276         case SENDER_IS_INITIATOR:
1277                 SIVAL(seq_num, 4, 0x80);
1278                 break;
1279         case SENDER_IS_ACCEPTOR:
1280                 SIVAL(seq_num, 4, 0x0);
1281                 break;
1282         }
1283
1284         DEBUG(10,("SCHANNEL: schannel_decode seq_num=%d data_len=%lu\n", a->seq_num, (unsigned long)data_len));
1285         dump_data_pw("a->sess_key:\n", a->sess_key, sizeof(a->sess_key));
1286
1287         dump_data_pw("seq_num:\n", seq_num, sizeof(seq_num));
1288
1289         /* extract the sequence number (key based on supplied packet digest) */
1290         /* needs to be done before the sealing, as the original version
1291            is used in the sealing stuff... */
1292         schannel_deal_with_seq_num(a, verf);
1293
1294         if (memcmp(verf->SequenceNumber, seq_num, sizeof(seq_num))) {
1295                 /* don't even bother with the below if the sequence number is out */
1296                 /* The sequence number is MD5'ed with a key based on the whole-packet
1297                    digest, as supplied by the client.  We check that it's a valid
1298                    checksum after the decode, below
1299                 */
1300                 DEBUG(2, ("schannel_decode: FAILED: packet sequence number:\n"));
1301                 dump_data(2, verf->SequenceNumber, sizeof(verf->SequenceNumber));
1302                 DEBUG(2, ("should be:\n"));
1303                 dump_data(2, seq_num, sizeof(seq_num));
1304
1305                 return False;
1306         }
1307
1308         if (memcmp(&verf->SignatureAlgorithm, &schannel_sig[0], 2) ||
1309             memcmp(&verf->SealAlgorithm, &schannel_sig[2], 2) ||
1310             memcmp(&verf->Pad, &schannel_sig[4], 2) ||
1311             memcmp(&verf->Flags, &schannel_sig[6], 2)) {
1312                 /* Validate that the other end sent the expected header */
1313                 DEBUG(2, ("schannel_decode: FAILED: packet header:\n"));
1314                 dump_data(2, (const uint8_t *)verf, sizeof(schannel_sig));
1315                 DEBUG(2, ("should be:\n"));
1316                 dump_data(2, schannel_sig, sizeof(schannel_sig));
1317                 return False;
1318         }
1319
1320         if (auth_level == PIPE_AUTH_LEVEL_PRIVACY) {
1321                 uchar sealing_key[16];
1322
1323                 /* get the key to extract the data with */
1324                 schannel_get_sealing_key(a, verf, sealing_key);
1325
1326                 /* extract the verification data */
1327                 dump_data_pw("verf->Confounder:\n", verf->Confounder,
1328                              sizeof(verf->Confounder));
1329                 arcfour_crypt(verf->Confounder, sealing_key, 8);
1330
1331                 dump_data_pw("verf->Confounder_dec:\n", verf->Confounder,
1332                              sizeof(verf->Confounder));
1333
1334                 /* extract the packet payload */
1335                 dump_data_pw("data   :\n", (const unsigned char *)data, data_len);
1336                 arcfour_crypt((unsigned char *)data, sealing_key, data_len);
1337                 dump_data_pw("datadec:\n", (const unsigned char *)data, data_len);
1338         }
1339
1340         /* digest includes 'data' after unsealing */
1341         schannel_digest(a, auth_level, verf, data, data_len, digest_final);
1342
1343         dump_data_pw("Calculated digest:\n", digest_final,
1344                      sizeof(digest_final));
1345         dump_data_pw("verf->Checksum:\n", verf->Checksum,
1346                      sizeof(verf->Checksum));
1347
1348         /* compare - if the client got the same result as us, then
1349            it must know the session key */
1350         return (memcmp(digest_final, verf->Checksum,
1351                        sizeof(verf->Checksum)) == 0);
1352 }
1353
1354 /*******************************************************************
1355 creates a new prs_struct containing a DATA_BLOB
1356 ********************************************************************/
1357 bool prs_init_data_blob(prs_struct *prs, DATA_BLOB *blob, TALLOC_CTX *mem_ctx)
1358 {
1359         if (!prs_init( prs, RPC_MAX_PDU_FRAG_LEN, mem_ctx, MARSHALL ))
1360                 return False;
1361
1362
1363         if (!prs_copy_data_in(prs, (char *)blob->data, blob->length))
1364                 return False;
1365
1366         return True;
1367 }
1368
1369 /*******************************************************************
1370 return the contents of a prs_struct in a DATA_BLOB
1371 ********************************************************************/
1372 bool prs_data_blob(prs_struct *prs, DATA_BLOB *blob, TALLOC_CTX *mem_ctx)
1373 {
1374         blob->length = prs_data_size(prs);
1375         blob->data = (uint8 *)TALLOC_ZERO_SIZE(mem_ctx, blob->length);
1376
1377         /* set the pointer at the end of the buffer */
1378         prs_set_offset( prs, prs_data_size(prs) );
1379
1380         if (!prs_copy_all_data_out((char *)blob->data, prs))
1381                 return False;
1382
1383         return True;
1384 }